1. Field of the Invention
The present invention relates to an image forming system, more particularly, to an image forming system including a finisher which is capable of applying postprocessing such as punching and stapling to printed or copied papers before discharging the printed or copied papers.
The present invention also relates to an image forming apparatus, more particularly, to an image forming apparatus having a function of printing on both surfaces of a paper.
2. Description of the Related Art
Generally, a finisher is used in combination with an image forming apparatus such as a printer or a copier. The printer or the copier discharges printed or copied papers sheet by sheet. When receiving the discharged papers, the finisher stacks them in sequence at one place. Or, the finisher opens punch holes in the received papers and thereafter stacks the received papers in sequence at one place. Then, the finisher staples a bundle of a certain number of the stacked papers.
In the image forming system including the finisher, an instruction to bundle and staple the printed papers or to open the punch holes in the printed papers is given by a command included in print command data. The contents designated by the print command data include information on a stapling position for stapling the papers, punching positions for opening the punch holes in the papers, and so on.
Further, in the system, in a case where the designated staple position is out of a movable range of a stapling mechanism or in a case where the designated punching positions are out of a movable range of a punching mechanism, the stapling instruction or the punching instruction itself is automatically deleted from the print command data. This prevents the system from stopping printing or becoming inoperable due to the inexecutable stapling instruction or punching instruction, and allows forcible continuation of print processing.
As a machine, such a system can be thought to be effective in that the progress of its print processing does not become stagnant and thus its operating efficiency is not lowered even if an inexecutable instruction is given. However, such an operation of the machine makes a user feel odd or distrustful about the machine because, if the machine actually finishes only the print processing regardless of the user's stapling or punching instruction which the user has surely given, the user cannot immediately understand why his/her instruction is disregarded. The user possibly misunderstands that the machine is out of order.
Further, when a user gives an inexecutable stapling instruction or punching instruction, the system deletes the user's instruction without a user's permission in pursuit of operating efficiency as a machine. Consequently, the system completely disregards the stapling or punching desired by the user, which is not convenient for the user. When the user definitely desires the postprocessing, the user has to take repeated trouble of setting the stapling position or punching positions in the system again, which lowers efficiency rather than improving it.
Therefore, a system having a finisher needs to realize improvement both in work efficiency and usability in a well-balanced manner.
Further, an image forming apparatus is generally capable of both single-sided printing and double-sided printing on a paper. However, if a medium not suitable for the double-sided printing such as, for example, used paper (with one side printed) or translucent paper is set in the image forming apparatus, the image forming apparatus does not execute a job in which the double-sided printing is instructed, even if a user tries to have the system execute the double-sided printing. This can prevent a mistake that the double-sided printing is erroneously executed on the paper not suitable for the double-sided printing and can save the waste of paper and toner.
Thus, from the viewpoint of preventing the user's erroneous copying, it can be indeed said to be effective that the image forming apparatus automatically stops its operation on its own judgment. However, if the image forming apparatus completely stops its operation without any notice only because a paper not suitable for the double-sided printing (used paper, translucent paper, or the like) is set, the work of the user waiting for the printing does not progress at all. This lowers work efficiency for many users.
Therefore, the image forming apparatus is required not only to simply reduce waste by preventing improper double-sided printing but also to contribute to improvement in work efficiency of a user.